Recently, several technologies that provide broadband data access have entered the market. These technologies include digital subscriber lines (DSL), cable modems, and wireless networks, among others. Another emerging technology uses existing electrical power distribution networks to carry high-frequency data signals to and from individual customer premises. Such systems may be referred to throughout as “power line communication systems.” Because electrical power distribution networks were designed to carry low-frequency high-voltage signals, however, transmitting higher frequency data signals often face obstacles not confronted by their lower frequency counterparts.
Many components create such obstacles to the higher frequency data signal. One particular element in the electrical power distribution network that creates a particular hindrance to the data signal is the electrical transformer. The transformer is an integral element in the electrical power distribution system that has been designed to efficiently step-down voltage to values consistent with customer equipment, while providing the necessary isolation and protection from higher voltage values. However, the efficiencies that have been designed to handle the voltage signals often have a detrimental consequence for the previously unanticipated transmission of data signals. Therefore, while the transformer provides a critical function for the transmission of low frequency power, it often creates an obstacle in the transmission of higher frequency data signals.
One particular impediment to the transmission of data signals is created by the inherent characteristics of the transformer itself. Typically, the construction of a transformer is such that its characteristic impedance for higher frequency data signals is significantly lower than the impedance encountered on the customer premise side of the transformer (e.g., local distribution lines and customer premise equipment). As a result, if a communications signal is injected at the transformer, a significant portion of the higher frequency data signal follows the path of least resistance directly into the transformer, instead of ideally traveling over the distribution lines and onto the customer premise. As a result, a great deal of the data signal's strength is lost to the transformer and never reaches the customer premise. This condition is found in most transformer units because the electrical power distribution network, of course, was designed without the concern of transmitting higher frequency data signals.
Therefore, there is a need to reduce the loss of the higher frequency data signals communicated on the electrical power distribution system.